1. The Field of the Invention
The present invention generally relates to the field of light curing devices incorporating LED light sources and, more particularly, to the field of heat sinks configured for dissipating heat generated by the light sources of the light curing devices.
2. The Relevant Technology
In the field of dentistry, dental cavities are often filled and/or sealed with photosensitive compounds that are cured when they are exposed to radiant energy, such as visible or ultraviolet light. These compounds, commonly referred to as light-curable compounds, are placed within dental cavity preparations or onto dental surfaces where they are subsequently irradiated by a light-curing dental device.
Many light-curing devices are configured with a fiber optic light wand for directing light from a light source into a patient""s mouth. The light source may comprise, for example, a lamp, a halogen bulb or a light-emitting diode (LED). One end of the light wand is placed close to the light source so that the light emitted from the light source will be directed into the light wand. One problem with light wands, however, is that they are generally unable to capture all of the light that is generated by the light source, particularly the light that is emitted from LEDs, which may be emitted at angles of up to about 120xc2x0.
One method for overcoming the limitations of light capture by light wands and for generally improving the efficiency of the light-curing devices is to place the light source(s) of a light-curing device at the tip of the light-curing device. This enables all of the light generated by the light source(s) to be directed within the patient""s mouth, at the desired application site. Although this generally overcomes the aforementioned problems associated with light wands, the proximity of the light source to the patient""s mouth can create a new problem. In particular, the heat that is generated by the light source(s) at the tip of the light-curing device can create discomfort to the patient when the tip of the light-curing device happens to come in contact or immediate proximity to the sensitive mouth tissues of the patient. Accordingly, it is desirable to minimize the heat at the tip of the light-curing device.
One method for minimizing the heat at the tip of the light-curing device is to mount the light source(s) on a heat sink that can generally conduct the heat away from the tip of the light-curing device. Heat sinks, which operate on the principles of conduction and convention, are well known in the art of thermodynamics. As is commonly understood, the ability of a heat sink to diffuse heat is generally controlled by the material properties and geometries of the heat sink. The arrangement and geometries of the mounting surfaces of the heat sink are also important factors to consider when determining how efficiently the heat sink is able to diffuse heat.
Recently, light-curing devices have been developed that utilize multiple light sources. One such design incorporates a plurality of LEDs that are spaced apart and mounted on opposing angled surfaces of the heat sink. This design is particularly useful because it enables the plurality of LEDs to generally surround and simultaneously irradiate dental cavity preparations and other application sites from a variety of angles. One disadvantage of this design, however, is that each of the multiple LEDs generate heat that must be diffused. Although a heat sink is incorporated within this multiple LED design, the arrangement of the LEDs and LED mounting surfaces is not conducive to the efficient diffusion of the heat. Rather, the arrangement of LEDs is such that a majority of heat is generated and accumulated at the tip of the heat sink, where it is logistically the most difficult to diffuse. In fact there is no existing heat sink for light-curing devices comprising a geometric arrangement of three mounting surfaces that is specifically designed to increase the efficiency of the heat sink, rather than relying solely on the thermally conductive properties of the heat sink.
Accordingly, in view of the foregoing, there is currently a need in the art for improved heat sinks for dental light-curing devices that comprise mounting surfaces that are configured in geometric arrangements conducive to the diffusion of heat generated by LEDs mounted thereon.
Briefly summarized, presently preferred embodiments of the present invention are directed to heat sinks for dental light-curing devices comprising LED mounting surfaces arranged in geometric configurations conducive to the diffusion of heat generated by the LEDs.
According to one presently preferred embodiment, a heat sink comprises three mounting surfaces configured for mounting three corresponding light sources. The heat sink may comprise any material having a conduction coefficient that facilitates the conduction of heat. Suitable materials include, but are not limited to any combination of aluminum, copper, silver, other metals, and other materials with high conduction coefficients.
The heat sink is preferably configured in size and shape to be inserted within a handheld dental light-curing device. According to one presently preferred embodiment, the heat sink comprises a body that has a generally cylindrical cross-sectional area. The diameter of the heat sink is preferably between about 0.25 inches and about 0.75 inches. The length of the heat sink, which extends between a proximal end and a distal end of the heat sink, is preferably between about 1 inch and about 6 inches. It will be appreciated, however, that the length, width and cross-sectional area of the body may vary to accommodate any desired configuration.
According to the preferred embodiment, the three mounting surfaces of the heat sink are disposed on a face that is located near the distal end of the heat sink. Each of the mounting surfaces is configured for mounting an LED light source, which may comprise a single LED, an LED array, or any combination of LEDs. The mounting surfaces of the heat sink may also be configured to mount any other light source that is capable of generating light suitable for curing light-curable compounds.
The three mounting surfaces preferably comprise planar surfaces that converge at a central intersection point that is recessed into the body, such that the face is approximately concaved. The surface-to-surface angle that occurs between any two of the planar surfaces is preferably an angle within a range of about 100xc2x0 and about 140xc2x0, with a most preferred angle of approximately 120xc2x0.
The three mounting surfaces are configured in a geometric arrangement that is specifically configured for minimizing the heat generated by the LEDs at the distal end of the heat sink, and which is generally conducive to the diffusion of heat generated by the LEDs.
According to one preferred embodiment, the mounting surfaces are symmetrically disposed on the face, with one of the three mounting surfaces disposed on a distal portion of the face and the two remaining mounting surfaces disposed on a proximal portion of the face. It will be appreciated that this arrangement causes one of the three mounting surfaces to be located closer to the distal end of the body than either of the two remaining mounting surfaces, which are preferably spaced an equal distance away from the distal end of the body. According to the preferred embodiment, the symmetry of the face is also aligned with the symmetry of the body, such that a line of symmetry extending between the two proximal mounting surfaces lies substantially parallel with a central axis of the heat sink.
It will be appreciated, however, that according to another embodiment, the line of symmetry of the face may be angularly offset from the central axis of the heat sink, such that the two proximal mounting surfaces are not spaced equally away from the distal end. It is also within the scope of the invention for the mounting surfaces to be asymmetrically spaced apart or aligned.
According to the preferred embodiment, each of the LED light sources mounted on the three mounting surfaces generates substantially equal amounts of light and heat. Therefore, the heat generated by the LED light sources that are mounted on the two mounting surfaces that are the furthest away from the distal end of the tip will be collectively greater than the heat that is generated by the LED light source that is mounted on the mounting surface adjacent to the distal end. Therefore, it will be appreciated that the geometric arrangement of the mounting surfaces of the inventive heat sink causes a majority of the heat that is generated by the three LED light sources to be generated near the body of the heat sink where the heat is more easily diffused through the body and away from the distal end of the heat sink body, rather than at the distal end, where it is logistically more difficult to diffuse the heat.
These and other benefits, advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.